Traffic congestion levels across the U.S. dropped 30 percent in 2011, according to a new report from INRIX, a transportation analytics platform.

According to the study, the first such global analysis of traffic congestion, 70 of the country's 100 most populated cities saw drops in traffic congestion.

The analysis attributes the decrease, the largest since 2008, to a slow economic recovery and increasing gas prices.

“The declines in traffic congestion across the U.S. and Europe are indicative of stalled economies worldwide,” said Bryan Mistele, INRIX president and chief executive officer. “In America, the economic recovery on Wall Street has not arrived on Main Street. Americans are driving less and spending less fueled by gas prices and a largely jobless recovery.”

The study's results suggest that economic concerns closely linked to driving. Those cities showing the largest drops in congestion were also the cities where gas prices were higher than the national average at their peak in April 2011 ($3.96), such as Los Angeles ($4.25), San Francisco ($4.25), and Honolulu ($4.48).

On the other hand, cities with employment growth exceeding the national average of 1.2 percent, such as Tampa (3.0 percent), Houston (3.2 percent), and Austin (2.1 percent), experienced the largest spikes in congestion.

Rest assured, however, there are still plenty of people stuck in traffic jams. According to the report, drivers idle for an average of 40 hours per year in the country's 10 most congested cities: